PetenAli's WBX 2500 engine build

[PetenAli]

I'm in awe!

[silverbullet]

Found a last-minute clearance snag when the crank was hard against the thrust washer, all sorted now
Rotating assembly coming together nicely:


Committed to the Vanistan-type oil pressure relief mod:

The blanking tube that gets bonded in place:

You can just see it peeking out of the oil pickup bore, before the pipe goes back in:

It closes off down the bottom of here:

The copper top barrel seals arrived today as well

[silverbullet]

More hours spent assembling, checking,dismantling, reassembling... repeat until brain dead.
Getting the cam peak lift correctly timed at 110 degrees showed up a small angular error in the camshaft notching, so I had to re-check the master one (old Oetti cam) and correct the cam for this build.
Got confused, went round in circles for a bit but got it sorted.
A chance thought showed up another example of how tight things get with an 82mm stroke...

There is daylight in the gap and the engine turns over, but a few thou'off the back of the pistons would give a little more peace of mind!

[Dazco]

That is a bit close

[PetenAli]

Taking lots of deep breaths!!! Complete faith in Ian's skills and assiduousness though.

[itchyfeet]

Taking lots of deep breaths!!! Complete faith in Ian's skills and assiduousness though.

I hope you are not paying an hourly rate looks like a great deal of time has gone into this.

[silverbullet]

This is where the time goes on a non-standard engine. It hasn't been a continuous build though! All the hard work is now done, just got to tickle those pistons and the short engine can be closed up.

[itchyfeet]

Are those copper barrel seals custom made or off the shelf? whats the benefits?

[silverbullet]

I had a batch made, they were waterjet cut. The OEM folded/wrapped shim type cannot be opened up to 98mm, they would fall to bits (would need a special fixture anyway)

[itchyfeet]

98mm Omega Pistons & Westwood cylinder barrels (UK made)

just interested, what would Omega and Westwood expect you to use?

[silverbullet]

There is no expectation, I sent them pattern parts and they copied them in more up to date materials. Westwood declined to source the bigger O-rings for the bottom of the barrels, not their thing but they did give me a lead to follow up.
Oettinger had someone like Reinz make special top barrel seals, so thats not an option.
Nothing wrong with soft copper, some full-on drag race engines use copper with a wire ring for ultra-high clamping pressures on engines making hundreds of bhp per cylnder.

[itchyfeet]

ahh I see
I was assuming you would use standard o ring seals but I suppose they are not ideal being stretched.
we use these people at work for seals
http://www.mantek.co.uk/" onclick="window.open(this.href);return false;

[silverbullet]

The top O-ring seal is the std green one, the bottom one is a 2.2 section oversize to suit the barrel.

[CJH]

Getting the cam peak lift correctly timed at 110 degrees....

Ian, when I measured my cam, I found that if I had the peak of the inlet timed to exactly 110 degrees, then the midpoint of the valve overlap was exactly on TDC - the profile seems very accurately cut. The OEM DJ cam has a slightly different profile of course, but I wondered if it was significant that the overlap midpoint on the OEM cam was some 4 degrees BTDC, so I checked with Mr Newman. He felt it would be slightly better to advance the cam a couple of degrees, so that the overlap is slightly before TDC, so as to get the gas charge in slightly quicker at higher revs. He did say the effect would be very small though.

This is how I've set mine up on the basis of his advice.

[silverbullet]

I was informed by a German chap that the Oettinger 2500's didn't take to high rpm usage (which has accounted for a few failures over the years) whereas a DJ can be made to peak at 7000 rpm with a mad cam and twin Webers...
I am building for torque, so if these engines have given their best by 5k and fall of at 5500 then that will be all to the good.
Scratching for a few peak bhp isnt the game here